1. Field of the Invention
The present, invention relates to a cooking apparatus that controls the heating operation according to the weight of an object to be cooked.
2. Description of Related Art
A cooking apparatus that controls the heating operation according to the weight of an object to be cooked is disclosed in Japanese Patent Application Laid-open No. 4-45318 (1992). This cooking apparatus has input means for setting the cooking parameters, weight setting means for setting the weight, weight unit storing means for storing the weight unit, cooking start instructing means for instructing to start cooking and heating means for heating the object to be cooked. Such an arrangement is made for setting the weight unit in this cooking apparatus that, in the initial state before setting by means of the input means and the weight, unit setting means, the weight unit stored in the weight unit storing means can be changed when it is instructed to start cooking by means of the cooking start instructing means.
With such an arrangement, it is not necessary to provide in operation control means a control key for changing the weight unit that, is generally rarely used after once being set. Because the heating control is usually carried out by means of a microcomputer and the number of input/output ports is limited, omitting the control key for changing the weight unit enables the limited number of the input/output, ports to be used for other functions, resulting in making the cooking apparatus user friendly.
By omitting the control key for changing the weight unit, the operation control means of the cooking apparatus having the weight unit changing function can be commonly used also in a cooking apparatus distributed to regions where it is not necessary to change the weight unit.
However, because this changing system of the weight unit is carried out not by the control key for changing the weight unit but by a control key for the cooking start, instruction, the weight unit is changed by a single key operation. Therefore, there is a possibility of changing the weight unit by mistakenly operating the control key without the intention of changing the weight unit.
Specifically, when a user connects the power plug of the cooking apparatus to a power out, let and turns on the power switch for the first time after purchasing it, it is highly probable that the user is not familiar with the operating procedure of the cooking apparatus. Usually, the user learns the operation procedure while consulting the instruction manual from then on. In such a case, the user may operate the control keys randomly without knowing the functions of the keys, or a child nearby may tamper with the control keys, resulting in the weight unit being changed in a single action although the user is not aware of the fact that the weight unit is changed because of unfamiliarity with the operating procedure. Thus the user may start cooking with the wrong weight unit being set.
When the unit of kg that has been initially set is changed to the unit of lb (pound), attempt to enter 1 kg actually results in entering 1 lb (approximately 0.45 kg) and, when cooking is carried out in a heating sequence based on this weight, the material to be cooked will not be sufficiently cooked.
On the contrary, when the unit of lb that has been initially set is changed to the unit of kg, attempt to enter 1 lb actually results in entering 1 kg. When the material is cooked in a heating sequence based on this weight, it will be over-cooked and eventually burned.